The art typically refers to systems for loading and unloading containers as “hook lift” systems and “cable hoist” systems. These systems have been extensively employed for the transport of various materials in the containers and have a pivotal tilt frame attached to the vehicle. In the usual case, containers are loaded or unloaded upon the bed of the truck or vehicle utilizing the hook lift system or the cable hoist system. One typical use for such systems is in the picking up and hauling of refuse. An open top or closed top container is typically delivered to, or picked up from, a point of use with either of these systems.
Cable hoist systems typically use a cable reeving system like, for example, the one shown in U.S. Pat. No. 5,460,473. In this type of a system, hydraulic cylinders are typically used to move the cable about a fixed sheave attached to the vehicle hoist frame. In the fully retracted position, the cable, which is wrapped around sheaves connected to the cylinders, is at its longest affective length and can be connected to the front end of a container located on the ground. As the cylinders extend, the effective length of the cable continuously shortens as it wraps around the cylinder sheaves and then finally around the sheave attached at the front end of the hoist frame. As the effective length of the cable gets shorter, the container is pulled up and onto the vehicle, which is usually in a tilted position to facilitate loading and unloading of the container.
With the tilt frame members, the frame upon which the containers are placed is pivotally connected near or at the distal end of the vehicle frame. Hydraulic cylinders are used to raise and lower the tilt frame relative to the vehicle frame. The tilt frame is actuated during loading and unloading of containers to assist in these procedures.
Some tilt frames on the transport vehicles have extendable end portions which aid in loading and unloading containers in a more efficient manner. See, for example, U.S. Pat. No. 4,986,719. The distal (rear) end of the frame has a moveable portion which telescopically slides out of the frame to extend the length of the frame. These systems, although useful, have durability and strength problems.
One problem with existing tilt frame vehicle systems is that the tilt frame on the vehicle typically must be raised to a significant height for the loading and unloading of the containers and thus these systems have difficulty being used indoors or in situations where the ceiling height is low. The vehicles with extendable end portions may be used in such circumstances, but are not sufficiently durable and require more floor space for loading and unloading.
Needs therefore exist for new types of loading and unloading systems that can load, transport, and unload all types of containers, and in all types of situations and with all types of container loads, regardless of the overhead clearance.
The present invention solves these problems by providing a tilt frame transport vehicle with an end portion that contains a hinged and hydraulically actuated end member (called a “tail”). The hinged end member (tail) allows loading and unloading of containers without the necessity of raising the tilt frame to an extreme angle. Some containers can be loaded and unloaded without raising the tilt frame at all.